How Ink-free Mobile Photo Printers Work

Just how vivid and durable are photos printed from the Polaroid PoGo?­

Polaroid

Let my pictures go! Will the pocket-sized device be the Moses of printers -- setting free the enslaved digital images trapped in phones and digital cameras everywhere? Perhaps, but it might take some more time working in the lab for PoGo to fulfill its promises.

Zink's ink-free paper is a descendent of old-fashioned, thermal fax paper technology. Fax paper is coated with special chemicals, and when heat is applied the paper darkens through a chemical reaction. Zink paper is different because it prints in color (as opposed to black and white, like fax paper).

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Zink paper also shares similarities with other printing methods, namely dye diffusion thermal transfer or dye sublimation methods. These methods print in color, but are complicated because they use a third material (such as a ribbon) that contains the ink, which needs to be melted down to the paper. The advantage of Zink is that there's no middleman -- the only materials it needs are the paper and printer.

The obvious advantage of the product is that it's small and light. It can satisfy instant gratification -- you don't have to wait to get home to a stationary printer to get finished prints of your images.

And eco-conscious people will find that the paper is recyclable (unlike thermal paper) and non-toxic. Also, because there is no ink cartridge or ribbon to dispose of, the printer produces no waste.

Given the advantages, you'd expect this technology to take the public by storm. But some drawbacks might prevent it from catching on, at least for a little while.

First, some users have complained that the quality of the photo produced by a mobile photo printer is subpar. One expert reviewer for PC Magazine, David Stone, claimed that half of his test photos came out with skewed coloration and that some were "washed out" [source: Stone]. He also tested the supposed water resistance the printer advertises and found that, although the photos sustain drops that are immediately wiped off, the image suffers if drops dry on it. Time will tell whether these kinks can be ironed out in later advances.

And finally, Stone confirms the obvious suspicion that heat affects these images post-printing (given that heat is creates the print in the first place). When he held a print up to a hot light bulb, the colors became altered. If you'll remember, it takes temperatures of at least 212 degrees Fahrenheit (100 degrees Celsius) to activate crystals in Zink paper. Although photos are unlikely to experience these temperatures normally, it's best to keep them away from hot areas, like the oven or stove. Unlike with thermal fax paper, temperatures are unlikely to get hot enough in a sun-baked car to affect Zink paper.

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­The PoGo prints only 2-inch by 3-inch photos; however, Zink can make much larger sizes.

Zink Imaging

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